Field of the Invention
The present invention relates to a helical scan magnetic recording/reproducing apparatus and, more particularly, to a rotary cylinder device having magnetic heads which are held in contact with a magnetic tape so as to scan the tape as a rotary cylinder rotates.
Generally, a helical scan type magnetic recording/reproducing apparatus has a rotary cylinder device carrying a plurality of magnetic heads which are adapted to be successively and alternatingly brought into contact with a magnetic tape, thereby forming recording tracks on the magnetic tape or scanning the tracks for the purpose of reproduction.
A known rotary cylinder device used in magnetic recording/reproducing apparatus of the type described has a rotary shaft and a rotary cylinder which is disposed in opposition to a stationary cylinder leaving therebetween a slight gap in an axial direction of the rotary shaft. The rotary cylinder has an end surface facing the stationary cylinder and an outer peripheral surface. Recesses are formed in the end surface of the rotary cylinder and open in an outer peripheral surface and extend therefrom radially inwardly of the rotary cylinder over a small distance. Each recess has a leading end surface and a trailing end surface as viewed in the direction of rotation of the rotary cylinder. Magnetic heads are fixed in the recesses of the rotary cylinder with outer extremities thereof projecting beyond the outer peripheral surface of the rotary cylinder.
A disadvantage of the above proposed rotary cylinder device resides in the fact that air is induced into the recesses during operation of the rotary cylinder device to cause the magnetic tape to contact the surfaces of the recesses, resulting in vibration and damage of the tape.